1992 Buick Century my car will not start

The radio comes on when I put the key in and I can jump start the car but it didn't go very far before it would hesitate while running. I parked it and two days later moved it down the street, more towards the alley. It started okay but now, three days after that, it won't even turn over. Radio still comes on, power windows work. What would the difference be between the distributor, alternator and starter/ignitiion? Do I need to get it computer diagnosed? I have little money but have a buddy who could help with parts replacement.